It is the overall objective of this research to understand the role of ion transport in the long term maintenance of lens transparency. This requires an assessment of the importance of cell to cell communication to transport mechanisms and an understanding of how the syncytial morphology of the lens, which places most of its cell membranes facing restricted extracellular clefts, affects ion transport. Such as understanding requires the use of both morphological and electrophysiological techniques. The specific aims for the proposed work are: 1) To determine the effect of known uncouplers on cell to cell coupling in normal and cataractous lenses. 2) To determine spatial variation in cell coupling in normal lenses. 3) To determine the extent of cell coupling between lens epithelial cells and between epithelial cells and surface fibers. 4) To determine the involvement of cell to cell coupling in several cataract models. 5) To determine electrical characteristics of lens epithelial cells. 6) To determine the effect of specific ionophores, temperature, and blockers on whole lens impedance. 7) To verify the existence of high resistance fiber membranes in the lens. 8) To determine the effect of Na pump blockers on lens electrical properties. 9) To determine the effect of the extracellular space on lens impedance. We plan to use the techniques of patch voltage clamp, electrical impedance, and newly developed techniques for lens morphology to investigate lens electrical properties in normal and cataractous lenses of mammals, chicks and frogs.